Automatic strip alignment system

ABSTRACT

In a strip-processing line in which the trailing end of a first strip is welded to the leading end of a second strip vertically spaced from the first strip, apparatus is provided for aligning one edge of the moving first strip with the corresponding edge of the clamped second strip. A carriage movable transversely of the strip carries a pair of edge sensors one in alignment with each strip. When the edges of the strip are out of vertical alignment, an alignment control operable by the sensor associated with the moving strip moves the moving strip transversely until the edges return to alignment. A control is provided to move the carriage into a rearward position away from the strip when the leading edge is not clamped and into a forward operative position when clamped. The carriage position control prevents operation of the alignment control until the leading edge of the second strip is clamped and its sensor is in alignment therewith.

United States Patent [72] Inventor Francis J. McGorry 128 VermillionDrive, Levittown, Pa. 19054 [2]] Appl. No. 849,816 [22] Filed Aug. 13,I969 [45] Patented Oct. 5, 1971 [54] AUTOMATIC STRIP ALIGNMENT SYSTEM 8Claims, 3 Drawing Figs. [52] US. Cl 242/57.l, 226/15, 242/786 [51] Int.Cl B6511 25/26 [50] Field of Search 242/57,

[56] References Cited UNITED STATES PATENTS 2,641,416 6/1953 McCleary eta1. 242/57.l 2,643,117 6/1953 Frisbie et a]. 242/57.1 2,735,630 2/1956Ziebolz..... 242/57.l 2,860,841 11/1958 .lacobsen 242/57.l 2,941,5726/1960 242/57.1 X

Densen et al.

2,990,173 6/1961 Melville 242/57 .l X 3,322,362 5/1967 Nordgren 242/57.l3,322,963 5/1967 Pages 242/571 X Primary ExaminerStanley N. GilreathAssistant ExaminerWerner H. Schroeder Attorney-Martin J. CarrollABSTRACT: In a strip-processing line in which the trailing end of afirst strip is welded to the leading end of a second strip verticallyspaced from the first strip, apparatus is provided for aligning one edgeof the moving first strip with the corresponding edge of the clampedsecond strip. A carriage movable transversely of the strip carries apair of edge sensors one in alignment with each strip. When the edges ofthe strip are out of vertical alignment, an alignment control operableby the sensor associated with the moving strip moves the moving striptransversely until the edges return to alignment. A control is providedto move the carriage into a rearward position away from the strip whenthe leading edge is not clamped and into a forward operative positionwhen clamped. The carriage position control prevents operation of thealignment control until the leading edge of the second strip is clampedand its sensor is in alignment therewith.

PATENTEU UBT 5197i SHEET 1 BF 2 INVENTOR FRANCIS J. MCG'ORRY m M hisAllarnay PATENTED BET 5197! SHEET .2 BF 2 IN VENTOR FRANCIS J. McGORRYa, m awq his Attorney AUTOMATIC STRIP ALIGNMENT SYSTEM This inventionrelates to an automatic strip alignment system and, more particularly,to a system for aligning the edges of vertically spaced strips. In acontinuous processing of strip, particularly steel strip, the commonpractice is to process one length of strip from a first uncoiler whileanother coil of strip is positioned in a second uncoiler and its leadingend squared off and held stationary at an in-line welding machine untilthe first coil is depleted. The trailing end of the first coil is thenheld stationary and welded to the leading end of the second coil. Unlessthe strips are properly aligned before the weld is made, offset weldswill occur which is detrimental for many reasons.

Prior to my invention, the edges of the strip were normally aligned bysight of eye. Since the strips are vertically spaced a distance ofseveral inches, errors of one-quarter inch or more commonly occur in thewelds.

lt is, therefore, an object of my invention to provide apparatus forautomatically aligning the edges of the strips before the weld is made.

This and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which:

FIG. I is a schematic view of a strip processing line having myinvention incorporated therein; and

H65. 2 and 2a when joined on lines A-A to -0 are a schematic diagram ofthe control system of my invention.

Referring more particularly to the drawings, reference numeral 1indicates the No. 1 uncoiler from which a coil of strip S is fed. A coilof strip SB is fed from No. 2 uncoiler 2. Hydraulic motors 3 and 4 movethe uncoilers l and 2 transversely. Oil is fed to one end of motor 3from pump 5 through conduit 6 and three-way solenoid valve 7 and to theother end through conduit 8 and three-way solenoid valve 9. The valves 7and 9 also control return flow of oil to pump 5 through conduits l0 and11, respectively. When solenoid 7S is energized, valve 7 will connectmotor 3 to conduit 6 and when deenergized to conduit 10. When solenoid9S is energized valve 9 will connect motor 3 to conduit 8 and whendeenergized to conduit 11. Oil is fed to one end of motor 4 from pump 5through conduit 12 and three-way solenoid valve 13 and to the other endthrough conduit 14 and three-way solenoid valve 15. The valves 13 and 15also control return flow of oil to pump 5 through conduits l6 and 17,respectively. When solenoid 135 is energized valve 13 will connect motor4 to conduit 12 and when deenergized to conduit 16. When solenoid 15S isenergized valve 15 will connect motor 4 to conduit 14 and whendeenergized to conduit 17. The strip passes over idler rolls 18 to awelding machine 19 and then around pinch rolls 20 through a looping pit21 to a strip-processing line 22 such as an electrolytic tinning line.The parts so far described, except for the solenoid valves, areconventional. v

According to my invention 1 provide an edge sensor assembly 24 betweenthe rolls l8 and welding machine 19. The assembly 24 includes a frame 26having vertically spaced traversing rods 28 extending transversely ofthe direction of travel of the strip. A traversing carriage 30 issupported on the rods 28 by means of rolls 32. A pair of edge sensors 34and 34B is provided in vertical alignment on the carriage 30 in linewith the top and bottom strips. These are preferably Lenco Model 163manufactured by Columbia Research Company. This is a radio frequencywave sensor having an area in its jaws where a signal change occurs whenmetal is present. A traversing rack 36 attached to the carriage 30 isdriven from a motor 38 through a gear reducer 40 and pinion 42. Powerfor driving motor 38 is provided from power source L1, L2 throughsilicon controlled rectifiers 44 or 46 connected in parallel. Thedirection of rotation of motor 38 is controlled by means of driver 48connected to rectifier 44 and driver 50 connected to rectifier 46. Thedrivers 48 and 50 supply the proper amount of current to turn on and offrectifiers 44 and 46 and may be Engineered Electronics Company Model No.T-l34. Normally open limit switches 52 and 54 are located adjacent thepath of travel of rack 36. The switch 52 limits forward travel of thecarriage 30 when it is opened by bracket 52B and switch 54 limitsreverse travel of the carriage 30 when opened by the carriage. Switches52 and 54 are connected in parallel to a 24 V. direct current powersource L3, L4 which is common to all relays. Switches 52 and 54 areconnected in series with relay coils 56 and 58, respectively. Relay coil56 has a normally closed contact 56C in series with rectifier 46 and anormally open contact 56Cl, which when closed operates a safety limitrelay to retract the carriage 30 out of the line. Relay coil 58 has anormally closed contact 58C in series with rectifier 44.

The output of sensor 34 is connected through a voltage divider 60 to theplus input of an operational amplifier 62 and the output of sensor 34Bthrough voltage divider 64 to the plus input of an operational amplifier66. Adjustable power sources 68 and 70 supply reference voltage to theminus input of amplifiers 62 and 66, respectively. The outputs ofamplifiers 62 and 66 are fed to position indicators 72 and 74,respectively, also to a motor control signal conditioning controlcircuit 76 through a normally closed contact 78C or a normally opencontact 78Cl operated by relay coil 78, and also to an uncoiler controlsignal conditioning circuit 80 through a normally open contact 82C or anormally closed contact 82C1 operated by relay coil 82. Circuit 76includes sensitivity rheostats 83 which determine the value of the errorsignal from amplifiers 62 and 66 which will activate the circuit 76.Relay coils 78 and 82 are connected in parallel with each other and inseries with normally open contact 84C operated by relay coil 84. Contact86 of a selector switch is connected in series with coil 84. When thetop strip S is stationary and the bottom strip SB running the operatorsets the switch so contacts 86 are open. Thus, the output of amplifier62 is fed to circuit 76 and that of amplifier 66 to circuit 80. When thetop strip is running and the bottom strip stationary the contacts 86 areclosed. Thus, the output of amplifier 62 is fed to circuit 80 and thatof amplifier 66 to circuit 76. Relay 84 also has normally open contacts84C1 and 84C2 and normally closed contacts 84C3 and 84C4.

Control circuit 76 includes a transistor 88 which controls a transistor90, the output of which is connected to a voltage comparator 92 which isconnected to driver 50. The circuit 76 also includes a transistor 94which controls a transistor 96, the output of which is connected todriver 48.

Control 80 is similar to control 76 and includes a transistor 98 whichcontrols a transistor 100, the output of which is connected to a voltagecomparator 102. Control 80 also includes a transistor 104 which controlsa transistor 106 and also sensitivity rheostats 107 similar to rheostats83. The comparator 102 is connected to an inverter 108, the output ofwhich is connected to an AND gate 110. Signals from drivers 48 and 50are also fed to gate 110. The only time gate 1 10 can be enabled is whenmotor 38 is not running and when running strip SB has moved forwardcausing its edge to move away from the center point of the signal changearea of its sensor. The output of gate 110 is fed to an AND gate 112 andan OR gate 114. Time controlled pulses of a one shot multivibrator 116is also fed to gate 112 to do the correcting. The pulses originate froma free running multivibrator 118 whose frequency is determined bycapacitors 120 and 122 and which is connected to multivibrator 116through capacitor 124. When gate 110 has a zero output, gate 112 becomesenabled for every correction pulse that appears at its input. Each timegate 112 is enabled it turns on driver 126 which is connected to andpicks up relay coils 128 and 130 depending which coil has voltageapplied to it through 84Cl or 84C3 which are connected in parallel witheach other in series with normally closed contact 132C of uncoiler andoil pump safety relay 132. Solenoid coil 78 is energized throughnormally open to 128C to control the position of uncoiler 1 and solenoidcoil 13S is energized through normally open contact 130C to control theposition of uncoiler 2.

The output of transistor 106 is connected to AND gate 138 which is alsofed from drivers 48 and 50. The output of gate 138 is fed to AND gate140 and also to gate 114. The output of multivibrator 116 is also fed togate 140. Gate 138 is only enabled when motor 38 is not running andstrip SB is running and has made a reverse movement error. gate 140turns driver 142 on and off at the pulsed rate. Driver 142 will pick uprelay coil 144 closing its contact 144C and complete a circuit tosolenoid coil 158, thus positioning uncoiler 2 and the strip SB in thecorrect position. With the strip S being fed from uncoiler 1, the driver142 will pick up relay coil 148 closing its contact 148C and complete acircuit to solenoid coil 9S, thus positioning uncoiler l and the strip Sin the correct position. Voltage is applied to coils 144 and 148 throughcontacts 84C4 and 84C2, respectively, which are connected in parallelwith each other and in series with contact 132C.

When an error in the position of the running strip occurs the OR gate114 is enabled and its output is inverted in inverter 152 and fed todriver 154 which enables relay coil 156 through contact 132C closing itscontact 156C to complete a circuit to relay coil 158 closing itsnormally open contact 158C. This completes a circuit to pump motor 159from power source L1, L2 causing the pump to run.

A relay coil 160 having a normally closed contact 160C is connected toDC power lines L3, L4 through contacts 162 and 164 which are closed whenthe mill is running. Also connected to DC power lines L3, L4 through apushbutton switch 166 is a relay coil 168 having a normally open contact168C and a normally closed contact 168C1. Contact 160C is connected topower source L3, L4 in series with coil 132. Thus, its normally closedcontact 132C will be open when the mill is not running and preventmovement of the coilers 1 and 2 and operation of pump 5. Relay coil 170is also connected in series with contact 160C. As long as the line isnot running its contacts 170C and 170C! are open. Since contact 170C isin the line from power source 68 and contact 170C1 in the line frompower source 70, the outputs of amplifiers 62 and 66 will be such as tocause the motor 38 to turn in the direction which will move the sensors34 and 348 out of the line. When the line is operating the referencevoltage is applied to the amplifiers 62 and 66 and the motor 38 willoperate to move the sensors into the line until they are correctlypositioned.

A safety limit relay coil 172 is connected to power source L3, L4through brass strips 174 and 1748 connected in parallel and attached tothe jaws of the sensors 34 and 348. Contact 56C1 is also connected inparallel with brass strips 174 and 1748. The same side of coil 1172 isconnected to a normally closed reset switch 176 and normally opencontact 172C. Relay coil 172 also operates a normally open contact 172C1connected in the circuit to coil 170. When contact 56C1 or the edge ofeither strip 174 or 174B contacts the top or bottom strip it picks upcoil 172 and locks itself in through contact 172C. Closing of contact172Cl causes relay 170 to pick up and move the sensors out of the line.Relay 172 will remain picked up until safety switch 176 is opened. Whenthis is done relay 170 drops out and the sensors now return into theline.

When switch"l66 is momentarily closed it causes relay coil 168 to pickup and lock it in through its contact 168C and a normally closedpushbutton switch 178. Thus, relay coil 168 remains energized untilswitch 178 is opened. Normally closed contact 168C1 is connected inparallel with contact 160C so as to keep relays 132 and 170 picked upand the sensors out of the operating line when relay coil 168 is notpicked up.

The operation of my control is as follows:

To calibrate the system, two pieces of metal are inserted into the jawsof sensors 34 and 34B with their edges in vertical alignment. When theyreach the centers of the signal change area of the sensors a DC voltageappears at the output of each sensor. With the installed circuit thisvoltage will be approximately 17.5 volts. The voltages appear at voltagedividers 60 and 64 and a portion thereof are fed to amplifiers 62 and66. Also fed into amplifiers 62 and 66 are the reference voltages fromadjustable voltage sources 68 and 70 and these reference voltages areadjusted until the output of each amplifier is zero as indicated onmeters 72 and 74.

The line can now be started with a coil of strip SB in the uncoiler 2.With the mill running, contacts 162 and 164 will be closed. Contact 86will be open so that relay contacts 84C3 and 84C4 are closed and 84C,84C] and 84C2 are open. At this time switch 166 is kept open so that mycontrol will not be in operation. A coil of strip S is then put onuncoiler 1 and the front end fed into the welding machine 19 and clampedin centered position with its edge becoming the control point. Switch166 is then momentarily closed to lock a coil 168 and close contact132C. Once the strip S is locked in position, the carriage 30 which hasbeen in retracted position will be moved forward due to the unbalance incarriage position amplifier 62 which will cause motor 38 to rotate inthe direction to move the carriage 30 forward until the strip S reachesthe center point of the signal change area of the edge sensor 34. Thisportion of the control then will be inoperative unless the stationarystrip S moves out of the center point of the signal change area.

The uncoiler control now comes into operation. As long as the edge ofthe strip SB remains in alignment with the edge of strip S nothinghappens. If the strip SB moves forward into the line an unbalance occursin amplifier 66 and a signal passes to uncoiler position control 80,which causes a signal to be applied to voltage comparator 102. Then, aspreviously described, relay coil 144 is energized to energize solenoid15S and relay coil 156 is energized to start up the pump. Energizationof solenoid 158 will cause valve 15 to open to conduit 14 and causecoiler 2 to move rearward until the edges of strip S and SB are aligned.If the strip SB moves rearward out of line with strip S, a signal ofopposite polarity will occur at amplifier 66 so that the signal fromcontrol will be applied to the AND gate 138. This, as described above,energizes relay coils 148 and 156. Energization of coil 148 completesthe circuit to solenoid 138 which will cause valve 13 to open to conduit12 and thus move coiler 2 forward until the edges of strips S and SB arealigned.

When strip SB is terminated its end will be welded to the forward end ofstrip S in the usual manner. However, just prior to this time, switch164 is opened to retract the carriage 30 out of the line. After welding,contact 164 is closed and uncoiling of strip S starts. Another coil ofstrip SB is then put on uncoiler 2 and the front end fed into the welder19 and clamped in centered position with its edge now becoming thecontrol point. Switch 166 is then depressed to energize and lock in coil168 and switch 86 is closed to energize coil 84. This closes contacts84C, 84C1 and 84C2 and opens contacts 84C3 and 84C4. Closing of contact84C energizes coils 78 and 82, thus connecting amplifier 62 to control80 and amplifier 66 to control 76. 1f the strip S moves transverselyforward an unbalance occurs in amplifier 62 and a signal passes tocontrol 80 which causes a signal to be applied to voltage comparator102. Then, as described above, relay coil 148 is energized to energizesolenoid 9S, thus causing uncoiler 1 to move rearward until the edges ofstrips S and SB are aligned and relay coil 156 is energized to startpump 5. 1f the strip S moves rearward out of alignment a signal ofopposite polarity will occur at amplifier 62 so that signal from control80 will be applied to the AND gate 138. This, as described above,energizes relay coils 128 and 156. Energization of coil 128 completesthe circuit to solenoid 7S which will cause valve 7 to open to conduit 6and thus move coiler 1 forward until the edges of strips S and SB arealigned.

When strip S is terminated the strips are welded end to end in the usualmanner after switch 164 is opened. The operation is then repeated with anew coil of strip S being provided.

While one embodiment of my invention has been shown and described, otheradaptations and modifications may be made.

lclaim:

1. Apparatus for aligning corresponding edges of lengths of stripspreparatory to fastening the strips end to end which comprises a pair ofuncoilers for mounting the lengths of strip in coiled form, a stripconnector located longitudinally from said uncoilers, means for movingsaid strips from said uncoilers in the direction of said strip connectorwith one strip spaced vertically above the other strip, means forseparately moving each of said uncoilers transversely, means forselectively clamping the ends of said strips from movement, an edgesensor associated with each of the top and bottom strips located betweensaid uncoilers and strip connector, an alignment control connected toeach of said sensors, and means operable when one of said strips isclamped and the other of said strips is moving longitudinally to causethe alignment control associated with the moving strip to move thatstrip and its uncoiler transversely until its edge becomes aligned withthe corresponding edge of the clamped strip, said top and bottom stripsbeing alternately moving and aligned with clamped bottom and top strips,respectively.

2. Apparatus according to claim 1 including a first amplifier connectedto said top sensor, a second amplifier connected to said bottom sensor,and means for connecting said first amplifier to said alignment controlwhen the bottom strip is clamped and connecting said second amplifier tosaid alignment control when the top strip is clamped.

3. Apparatus according to claim 1 including a transversely movablecarriage, means mounting said edge sensors on said carriage in verticalalignment one associated with the top strip and the other associatedwith the bottom strip, means for moving said carriage into a forwardposition in which said sensors are adjacent one edge of the lengths ofstrip and to a rearward position away from said strip, a carriageposition control for operating said carriage-moving means when theleading end of a strip is clamped in position, means connecting thesensor of said clamped strip to said carriage position control, andmeans operable by said carriage position control when he edge of saidclamped strip is out of line with its sensor to cause said carriagemoving means to move said carriage in the proper direction to being saidedge and associated sensor into alignment.

4. Apparatus according to claim 3 including means operable by saidcarriage position control to prevent operation of said alignment controlexcept when said clamped strip edge is in alignment with its sensor.

5. Apparatus according to claim 4 including a first amplifier connectedto said top sensor, a second amplifier connected to bottom of sensor,and means for connecting said first amplifier to said carriage positioncontrol and said second amplifier to said alignment control when the topstrip is clamped and connecting said first amplifier to said alignmentcontrol and said second amplifier to said carriage control when thebottom strip is clamped.

6. Apparatus according to claim 5 in which the means for moving eachuncoiler transversely is a fluid motor, and in which the first andsecond amplifiers are operational amplifiers.

7. Apparatus according to claim 6 including a pump for supplying fluidto said fluid motors, and means operable by said alignment control forstarting said pump in operation when said moving strip is out ofalignment with said clamped strip.

8. Apparatus according to claim 3 including a first amplifier connectedto said top sensor, a second amplifier connected to said bottom sensor,and means for connecting said first amplifier to said carriage positioncontrol and said second amplifier to said alignment control when he topstrip is clamped and connecting said first amplifier to said alignmentcontrol and said amplifier to said carriage control when the bottomstrip is clamped.

1. Apparatus for aligning corresponding edges of lengths of stripspreparatory to fastening the strips end to end which comprises a pair ofuncoilers for mounting the lengths of strip in coiled form, a stripconnector located longitudinally from said uncoilers, means for movingsaid strips from said uncoilers in the direction of said strip connectorwith one strip spaced vertically above the other strip, means forseparately moving each of said uncoilers transversely, means forselectively clamping the ends of said strips from movement, an edgesensor associated with each of the top and bottom strips located betweensaid uncoilers and strip connector, an alignment control connected toeach of said sensors, and means operable when one of said strips isclamped and the other of said strips is moving longitudinally to causethe alignment control associated with the moving strip to move thatstrip and its uncoiler transversely until its edge becomes aligned withthe corresponding edge of the clamped strip, said top and bottom stripsbeing alternateLy moving and aligned with clamped bottom and top strips,respectively.
 2. Apparatus according to claim 1 including a firstamplifier connected to said top sensor, a second amplifier connected tosaid bottom sensor, and means for connecting said first amplifier tosaid alignment control when the bottom strip is clamped and connectingsaid second amplifier to said alignment control when the top strip isclamped.
 3. Apparatus according to claim 1 including a transverselymovable carriage, means mounting said edge sensors on said carriage invertical alignment one associated with the top strip and the otherassociated with the bottom strip, means for moving said carriage into aforward position in which said sensors are adjacent one edge of thelengths of strip and to a rearward position away from said strip, acarriage position control for operating said carriage-moving means whenthe leading end of a strip is clamped in position, means connecting thesensor of said clamped strip to said carriage position control, andmeans operable by said carriage position control when he edge of saidclamped strip is out of line with its sensor to cause said carriagemoving means to move said carriage in the proper direction to being saidedge and associated sensor into alignment.
 4. Apparatus according toclaim 3 including means operable by said carriage position control toprevent operation of said alignment control except when said clampedstrip edge is in alignment with its sensor.
 5. Apparatus according toclaim 4 including a first amplifier connected to said top sensor, asecond amplifier connected to bottom of sensor, and means for connectingsaid first amplifier to said carriage position control and said secondamplifier to said alignment control when the top strip is clamped andconnecting said first amplifier to said alignment control and saidsecond amplifier to said carriage control when the bottom strip isclamped.
 6. Apparatus according to claim 5 in which the means for movingeach uncoiler transversely is a fluid motor, and in which the first andsecond amplifiers are operational amplifiers.
 7. Apparatus according toclaim 6 including a pump for supplying fluid to said fluid motors, andmeans operable by said alignment control for starting said pump inoperation when said moving strip is out of alignment with said clampedstrip.
 8. Apparatus according to claim 3 including a first amplifierconnected to said top sensor, a second amplifier connected to saidbottom sensor, and means for connecting said first amplifier to saidcarriage position control and said second amplifier to said alignmentcontrol when he top strip is clamped and connecting said first amplifierto said alignment control and said amplifier to said carriage controlwhen the bottom strip is clamped.